QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Mykkanen, H. M. Articles by Wasserman, R. H. Search for Related Content PubMed PubMed Citation Articles by Mykkanen, H. M. Articles by Wasserman, R. H.

Effect of Phosphate on the Intestinal Absorption of Lead (²⁰³Pb) in Chicks¹

Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca, NY 14853

The effect of phosphate on the intestinal absorption of lead (²⁰³Pb²⁺) was examined in chicks. Absorption was determined by the in situ ligated duodenal loop technique. In one approach, diets differing in phosphate content were fed to 2-week-old chicks for a period of 7 days. With respect to the control group (1.06% P), a severe phosphate deficiency (0.16% P) decreased growth, CaBP synthesis and ²⁰³Pb absorption; a moderate phosphate deficiency (0.33% P) resulted in an increase in CaBP production and ²⁰³Pb absorption; and the high phosphate diet (2.12%) gave mean values for CaBP synthesis and ²⁰³Pb absorption intermediate between those from the chicks fed the 0.33 and 1.06% diets. ²⁰³Pb absorption was highly correlated with CaBP concentrations. In another approach, phosphate in varying concentrations was added directly to the dosing solution. In one study, phosphate addition (0.1 mM) depressed ²⁰³Pb absorption in rachitic and cholecalciferol-treated chicks. When the data were expressed in terms of absorption of the soluble ²⁰³Pb present in the intestinal lumen at the end of the absorption period, an effect of phosphate in addition to the precipitation of the insoluble lead salt was uncovered. In an experiment with normal chicks, it was observed that phosphate in the dosing solution at concentrations of 1 and 2 mM partially and significantly reversed the inhibitory effect of lower concentrations of phosphate (0.01 mM and 0.1 mM). These data demonstrate the complexity of the phosphate-lead interaction, in addition to directly showing an effect of dietary phosphate on intestinal lead absorption.

KEY WORDS: • lead • phosphate • calcium-binding protein (CaBP)

¹ Supported by Department of Energy Contract DE-AC02-76EV02792 and by National Institutes of Health Grant AM-04652.

Manuscript received 27 April 1983.